Inside a lens barrel, various electrical control mechanisms are provided such as, for example, a shutter drive mechanism, a focusing motor, a zooming motor and a shake-prevention mechanism. An FPC board, which comprises a flexible printed circuit board, is used to electrically connect the control mechanisms with control circuits and electric components outside the lens barrel.
This type of FPC board has one end connected to the circuit boards within the lens barrel where the electric components are mounted, while the other end is connected to circuit boards provided outside the lens barrel (where control circuit components such as control ICs are mounted) after the FPC board is wired by being bent several times around the space inside the lens barrel. Accordingly, electrical components in the mechanism inside the lens barrel and electrical components outside the lens barrel are electrically connected via wire patterns on the FPC board.
When this type of FPC board is used, the FPC board can respond through suitable deformation to movement in the direction of the optical axis by the electrically controlled mechanisms having electrical components, accompanying movement of a lens group such as the zooming lens, and thus, the FPC board does not place an undue burden on the lens group.
However, when an attempt is made to connect this kind of electrically controlled mechanism within the lens barrel to other mechanisms within the lens barrel or to electrical components outside the lens barrel using the FPC board, the following problems arise.
The electrically controlled mechanisms are supported by the optical system support unit that is supported inside the lens barrel so as to be capable of movement, but there are many limiting conditions on the arrangement of electrical connections in these mechanisms when the mounting and arrangement within the lens barrel of the FPC board used as a wiring device are taken into consideration. In particular, placing all of the electrical connections of the mechanisms contained in the support unit at one side of the support unit is structurally impossible.
In addition, when an attempt is made to expose electrical connections on both sides of the support unit and to connect each of these through FPC boards, a plurality of FPC boards must be used due to the positional relationship of the connections and the wiring connection structure. Moreover, the number of wiring patterns on these circuit boards must be increased, making it necessary to formulate countermeasures such as connecting these with wires at suitable locations.
Consequently, with the conventional structure there are real problems and difficulties in terms of the number of FPC boards and in wiring the structure, as well as in connecting the various connecting ends of the FPC boards to the connections on the mechanisms, and there are also problems in terms of ease of assembly, assembly cost and production costs. In addition, space is also necessary for the connections of the FPC boards and for the mounting of each of the FPC boards, creating the problem that it becomes impossible to make the lens barrel, and the camera as a whole, compact.
In particular, when a plurality of FPC boards are used and each of these is connected with wiring at the appropriate location, it is also necessary to ensure beforehand that each board is connected to the mechanisms. Accordingly, assembly becomes difficult, and the wiring becomes more complicated. This creates the need for countermeasures that solve these problems.
In addition, various components such as the automatic exposure mechanism and automatic focus mechanism have been made electronic and have been largely automated. However, one area that has remained inadequate in attempting this kind of automation in cameras is that of measures to counteract image shaking caused by camera shaking, for example, which is produced during hand held photography.
For this reason, a shake-prevention device has been proposed for this type of camera to prevent image shaking caused by the shaking of the camera during photography, such as by inclining or vibrating the camera. Prevention is effected by detecting camera shake conditions using a shake detection device, by providing the shooting lens system (main optical system) or a part of the optical system with a shake-prevention optical system (hereinafter referred to as the shake-prevention lens), and by causing this system to shift in a direction perpendicular to the optical axis.
In addition, various electrical drive mechanisms are positioned inside the lens barrel of the above-described camera, such as, for example, drive mechanisms including the shutter drive mechanism, the focusing motor and the zooming motor.
Furthermore, it is necessary to conduct rotational drive position detection on the drive mechanisms thus contained inside the above-described lens barrel, for which reason sensors such as photo-interrupters are generally also contained within the lens barrel.
However, with the above-described electrical drive mechanism, the mounting structure of the motor, which comprises the drive source, is a problem. In addition, the mounting structure of the pair of photo-interrupters, which are included as rotation detection sensors, also presents a problem, as does the motor.
In other words, a problem exists with the conventional structure in that the structure is complex and assembly is also complicated. Furthermore, with the above-described structure, because assembly of the various components is complicated, a problem also exists in that maintenance is difficult, and assembly and removal of the components is troublesome.
In particular, with the described conventional structure, it is necessary to use a unit having a complex shape as the support unit that serves as a base for the mechanism where the various components are provided, making the production processes troublesome, and making it difficult to simply mold the unit, creating problems in terms of cost. It is thus desirable to create countermeasures to overcome these problems.
Heretofore, the mounting circuit board anchored on a camera body and the electric components within the lens barrel in the electric circuit boards of a camera have been connected by a piece of FPC (flexible print circuit board). (See, for example, Japanese Laid Open Patent Application No. 3-160594.) In such a camera, the shutter unit and the focus unit are placed inside the camera and are usually integrated as one unit; thus, electric components are located in one place, making it easier to connect the FPC.
However, in order to realize higher functionality, a super compact size, and better cost effectiveness, innovations such as the introduction of anti-vibration components to prevent shaking inside the lens barrel, and a structure in which the shutter unit and the focus unit are separated, have been implemented in recent cameras.
Because of such innovations, more electric components became necessary inside the lens barrel. Moreover, it has become impossible to place all of the electric components in one place, and the FPC has become more complicated in structure.
Moreover, it has become impossible to connect all the electric components with one FPC. Although it is possible to provide a second FPC to be connected to the conventional (first) FPC, this requires space to connect the first FPC and the second FPC, presenting yet another obstacle in making a camera super compact.